Kinetic modelling of lactic acid production from whey byLactobacillus casei (NRRL B-441) (original) (raw)
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Kinetic model of growth and lactic acid production from lactose by Lactobacillus bulgaricus
Process Biochemistry, 1993
Batch and continuous fermentation kinetics of Lactobacillus bulgaricus were examined in detail. The batch kinetic model includes the effect of pH, lactate and substrate. The effect ofpH on the enzyme /3galactosidase is reflected in the value of pu,ll,, the Monad's growth constant. Empirical expressions to estimate model parameters based on pH were established. These werehrther used to estimate the ceil mass and lactic acid concentration for the fermentation proceeded with no pH control. At high pH lactic acid was mostly formed by growth associated mechanisms and at IowpH it was due to the cell maintenance. The relationship between ATP concentration and cell mass in a batch fermentation could be approximated by a Leudeking-Piret like relationship. The continuous fermentation was studied with valyingpH and initial substrate conditions. A maximum productivity of 6.2 gjlitre per hour was obtained atpH 56 for the CSTR system, which was three times the productivity obtained for a batch system at the same PH. The CSTR system had a high productivity over a very small range of retention times. Three stages were found to he sufficient to utilize completely the lactose, but at the cost of decreasing the productivity to 48 g/litre per hour.
Batch production ofL(+) lactic acid from whey byLactobacillus casei(NRRL B-441)
Journal of Chemical Technology & Biotechnology, 2004
The effects of temperature, pH, and medium composition on lactic acid production by Lactobacillus casei were investigated. The highest lactic acid productivity values were obtained at 37 • C and pH 5.5. The productivity was 1.87 g dm −3 h −1 at 37 • C in shake flasks. In the fermenter, a productivity of 3.97 g dm −3 h −1 was obtained at pH 5.5. The most appropriate yeast extract concentration was 5.0 g dm −3 . Whey yielded a higher productivity value than the analytical lactose and glucose. Initial whey lactose concentration did not affect lactic acid productivity. MnSO 4 ·H 2 O was necessary for lactic acid production by L casei from whey. Product yields were approximately 0.93 g lactic acid g lactose −1 .
Fermentative Lactic Acid Production by Lactobacilli: Moser and Gompertz Kinetic Models
2017
Lactic acid production in a batch submerged fermentation process by five Lactobacilli: bulgaricus, casei, lactis, delbrueckii and fermentum in lactose fortified whey culture were investigated. Kinetic behavior of Lactobacilli growth rate and lactose utilization was studied based on the Moser and Gompertz kinetic models. Trendline tool in Excel software was applied for fitness assessment of the experimental data to investigate the kinetic models. Lb. bulgaricus had shown the best cell production yield of 0.119 g.g-1 of consumed lactose. Also, maximum lactic acid production yield of 0.602 g.g-1of consumed lactose was obtained by Lb. bulgaricus. Lb. bulgaricus (R2=0.954, μmax=0.5 and Ks=9.385) and Lb. casei (R2=0.956, μmax=0.580 and Ks=18.2) have showen acceptable consistency with Moser kinetic model. Moser kinetic model isn't a desired model to describe the cell growth and substrate consumption behavior of Lb. fermentum, Lb. delbrueckii and Lb. lactis. None of the investigated st...
Journal of Chemical Technology & Biotechnology, 2005
Growth of Lactobacillus helveticus on supplemented whey permeate was divided into five phases: lag, exponential, deceleration, stationary and decline phases. Each phase was characterized by simple model kinetics. From this and by considering a partial association of lactic acid production with growth, with an additional term introduced to account for cessation of production when the carbon substrate became limiting, the lactic acid production was analytically deduced for each growth phase. For both growth and production data, on the whole culture, the calculated values were found to match experimental data. All the model parameters can be easily deduced from experimental data. The model allows therefore a fine analysis of growth and production kinetics.
Kinetics of growth and lactic acid production from whey permeate by Lactobacillus helveticus
The Canadian Journal of Chemical Engineering, 1987
Batch fermentation kinetics of Lactobacillus helveticus were examined in detail. The nature of the culture medium had a significant effect on the product synthesis mechanism. In a glucose synthetic medium, lactic acid produced by the non-growth-associated mechanism was less than that by the growth-associated mechanism. In a lactose synthetic medium, the contribution of both mechanisms was approximately equal at the end of fermentation. In the whey-yeast extract permeate medium, the contribution by the non-growth-associated mechanism was superior to that of the growthassociated mechanism. Temperature and pH also influenced the relative contribution of the two mechanisms on the total production of lactic acid in whey-yeast extract permeate medium. Under optimal conditions for temperature and pH, the contribution of non-growth-associated product formation was the highest among all temperatures, and the lowest among all pH's. The ATP concentration-biomass concentration relationship in the batch fermentation process could be roughly approximated by a Luedeking-Piret-like equation.
Effect of different media on production of lactic acid from whey by Lactobacillus bulgaricus
Whey containing 50 g.l -1 lactose was fermented to lactic acid in batch process by Lactobacillus bulgaricus. The impact of 5 different media with change in volume percent of whey and nutrient was investigated at 32 0.5°C. Substrate consumption and lactic acid production were determined at 0, 12, 24, 36, 48, 60 and 72 h. In these experiments, the volume percent of whey and nutrient was changed and highest lactic acid production (20.8 g/l) and rate of productivity (0.304 g/l.h) was achieved when the volume percent of whey was 80 (volume percent of nutrient diluted with water 20). The minimum rate of process was observed at the highest nutrient percent (50%), and at highest volume percent of whey in the medium (99%), inhibition occurred.
A study on the effect of parameters on lactic acid production from whey
Polish Journal of Chemical Technology, 2016
In batch fermentation of whey, selection of suitable species at desired conditions such as substrate, product concentrations, temperature and inoculum size were investigated. Four Lactobacillus species and one Lactococcus species were screened for lactic acid production. Among them L. bulgaricus ATCC 11842 were selected for further studies. The optimal growth of the selected organism for variable size of inocula was examined. The results indicated that inoculum size had insignificant effect on the cell and lactic acid concentration. The effect of temperature was also studied at 32, 37, 42 and 47°C. Results showed that the concentration of cell dry weight increased with increment of temperature from 32 to 42°C. The maximum cell and lactic acid concentration was obtained at 42°C. The effect of initial substrate concentration on lactic acid production was also examined. The optimum initial lactose concentration was found to be 90 g/l.
Enzyme and Microbial Technology, 2001
The Luedeking and Piret expression can not account for the cessation of production observed at the end of batch; so an empiric term has been previously added to this equation which accounted in a global way for possible substrate limitations. In the model developed in this work, a carbon substrate limitation appeared explicitly in the production expression. Assuming a sigmoidal variation with time of specific growth rate previously validated, the new production model matched well the entire experimental production kinetics. It has been successfully tested for a wide range of nitrogen supplementations, i.e. from an almost total coupling between growth and production for largely supplemented media, to a high decoupling in case of few available nitrogen. Since all the parameters of this model have an obvious biologic meaning, it may be an unvaluable tool for the comprehension of the phenomenon. The model accounted also well for the variation of the specific production rate versus specific growth rate, avoiding the noise due to the direct differentiation of experimental data.
The effects on the lactic acid (LA) production by thermophile Lactobacillus bulgaricus ATTC 11842 on whey as a basal medium of seven factors namely, temperature °C, pH, Lactose g/l, Yeast extract g/l, corn steep liquor (CSL) g/l, K 2 HPO 4 g/l, and salts g/l (MnSO 4 , MgSO 4 and FeSO 4 ) were investigated, through the statistical analysis of the results by Plackett and Burmann experimental design. pH was found to have the high significant effect on lactic acid production. By response surface methodology (RSM) design the optimal value of pH and concentrations in the medium of yeast extract, K 2 HPO 4 and salts were then investigated, it should be 5.5 of pH, 2.73 g/l of K 2 HPO 4 , 1.59 g/l of yeast extract and 0.0326 g/l, 0.1304 g/l, 0.01304 g/l of MgSO 4 , MnSO 4 and FeSO 4 respectively. The results obtained with the optimal results were 20.9592 g/l. of lactic acid and the corresponding yields was 0.5665% (ratio between the amount of lactic acid produced and the initial concentration of lactose).